GEOLOGY I YOUNG STUDIES f UNIVERSITY Volume 12 December 1965 r' r' CONTENTS Thrusting in the Southern Wasatch Mountains, Utah ........ Michael J. Brady 3 Nebo Overthrust, Southern Wasatch Mountains, Utah ........ B. Allen Black 55 Paleoecologic implications of Strontium, Calcium, and Magnesium in Jurassic rocks near Thistle, Utah .... Button W. Bordine 91 Paleoecology of the Twin Creek Limestone In the Thistle, Utah area .................................... .... .....Ladell R. Bullock 121 Geolo of the Stockton stock and related intmsives, &1e County, Utah ................................................. John L. Lufkin 149 Stratigraphy and rifera of Ordovician rocks near Columbia Iceads, Jasper National Park, Alberta, Canada .............................................................. .. .... J. Keith Rigby 165 Lower Ordovician conodonts and other microfossils from the Columbia Icefields Section, Alberta, Canada ........................... .. .......... R. L. Ethington and D. L. Clark 185 Publications and maps of the Geology Department ........................... .. ..... 207 Brigham Young University Geology Studies Volume 12 - December 1965 Contents Thrusting in the Southern Wasatch Mountains, Utah ........ Michael J. Brady 3 Nebo Overthrust, Southern Wasatch Mountains, Utah ........ B. Allen Black 55 Paleoecologic irriplications of Strontium, Calcium, and Magnesium in Jurassic rocks near Thistle, Utah .... Burton W. Bordine 91 Paleoecology of the Twin Creek Limestone in the Thistle, Utah area .................................................... Ladell R. Bullock 121 Geology of the Stockton stock and related intrusives, Tooele County, Utah .................................................... John L. Lufkin 149 Stratigraphy and porifera of Ordovician rocks near Columbia Icefields, Jasper National Park, Alberta, . Canada .......................................................................... J. Kelth Rlgby 165 Lower Ordovician conodonts and other microfossils from the Columbia Icefields Section, Alberta, Canada ............................................ R. L. Ethington and D. L. Clark 185 Publications and maps of the Geology Department ........................................ 207 A publication of the Department of Geology Brlgham Young University Provo, Utah 84601 Ed~tor J. Keith Rigby Editorial Staff Lehi F. Hintze Myron G. Best Brzgham Your~gUniuerszty Geology Studres is published annually by the Department. Geology Studies consists of graduate student and staff research in the Department and occasional papers from other contributors, and is the successor to BYU Research Studies, Geology Serier, published in separate numbers from 1954 to 1960. Distributed December 31, 1965 Prrce $4.00 Stratigraphy and Porifera of Ordovician Rocks Near Columbia Icefields Jasper National Park, Alberta, Canada J. KEITHRIGBY Brigham Young Univerjjty ABSTRA~~.-A~excellent and readily accessible section of Lower and Middle Ordovician Mons to Mount Wilson Formations is exposed in creek banks immediately northeast of the campground at Columbia Icefields Chalet, Jasper National Park, Alberta. The Mons Formation is an argillaceous unit with interbedded bioclastic and intraformational conglomeratic limestone. It is overlain gradationally by abundantly fossiliferous limestone of the Sarbach Formation. Small sponge reefs occur in the basal beds of the Sarbach Formation. Upper beds, pisolitic dolomite of the Skoki Formation and a laminated silty dolo- mite of an unnamed formation, are only sparingly fossiliferous. The boundary between dclomitic units is placed at a bed of large silicified gastropods. The sandy to vitreous Mount Wilson Quartzite is the upper formation of the iocal Ordovician section and is unconformably overlain by the Devonian Fairholme Group. Anthaspidellid, hexactinellid, and heteractinellid sponges occur in the section, but only anthaspidellid forms are abundant and these only in small reefs at the base of the Sarbach Formation. The anthaspidellid sponges are among the oldest known lithistid forms. CONTENTS TEXT ILLUSTRATIONS figure Page Introduction ........................................ 165 1. Index map ................................ 166 Locality and Method of Study ............ 166 2. Erosional log of Columbia Ice- fields Section ............................ 168 Acknowledgnlents ............................. 166 Stratigraphy ........................................ 166 plate Page Lyell ( ?) Formation ........................ 166 1. Vicws of Mons and Sarbach Mons Formation ................................ 169 outcrops ........ following page 175 Aae and Thickness .................... 170 2. Exposures of Sarbach lime- stone ................ following page 175 Sarbach Formation ........................... I 70 3. Photomicrographs of Mons and Age and Thickness .................... 171 Lyell ( ?) limestones Skoki Formation ................................ 171 ........................ following page 175 I Tnnamed 1:ornlation ...................... 172 4. Photomicrogra~hs of Sarbach Paleontology ...................................... 172 and Younger carbonates Demos~>oneea. - .................................. 171 ........................ following page 175 Hexactinellida ............................. 177 5. Sponge photomicrographs ....................... following page 175 Appendix ............................................ 178 6. Suonee ~hotomicroeraohs References Cited ................................ 183 ........................ following page 175 INTRODUCTION Ordovician rocks are exposed in the Canadian Rocky Mountains in a northwesterly trending belt in some of the Front Ranges, Main Ranges, and Western Ranges (Norford, 1963, fig. 4-9). North and Henderson (1954, p. 62-68 and 196) have summarized known outcrops and thicknesses as part of a broad review of geology between latitudes 49'30' and 52'30' north and Norford (1963, p. 42-48) has done the same between latitudes 49' to 59O. 166 J. KEITH RIGBY Few of these outcrops have been studied in detail, and published stratigraphic sections or paleontologic data are not common. Walcott (1928) early subdivided the Lower Ordovician rocks of the Saskatechewan River Crossing region into the Mons and Sarbach Formations, largely because the Mons Formation contained an "Ozarkian" fauna, as con- trasted with the "true Ordovician" fauna of the overlying Sarbach rocks. At the same time, he proposed the Skoki Formation for outcrops near Fossil Mountain (Text-fig. 1) to the southeast. It has been common practice to group the formations in regional field work. The Sarbach, Mons, and Skoki Forma- tions are mappable at least from the Mount Wilson area at Saskatchewan Cross- ing to the vicinity of Sunwapta Pass and Columbia Icefields, more than 30 miles, some distance beyond Walcott's area of investigation.- Although Walcott's original reason for subdivision was faunal, various persistent lithologic units can also be utilized in subdivision of the section, at least in the area of consideration. Subsequent workers, in addition, have shown that the original Mons Formation includes not only Lower Ordovician rocks, --------- 'L ---- :----------L Clearwater Canyon TEXT-FIGURE\.-Index map of the measured section and of certain other sections re. ferred to by Walcott and others. ORDOVICIAN STRATIGRAPHY AND SPONGES 167 but some Upper Cambrian as well, although in most sections the boundary between the two systems is difficult to place. Allan (1938) discussed the Cambrian and overlying rocks of the Sunwapta Pass area, immediately southeast of the Columbia Icefields, and included some of the presently considered Ordovician in his sequence. Later, Severson (1950) mentioned Ordovician rocks below the Mount Wilson Quartzite as incidental to his paper on the Devonian sequence in the immediate area. A more recent paper concerning the geology in this vicinity is that of Hughes (1955), who described the areal geology of the Tangle Ridge area and described but did not name the Lower Ordovician rocks. Norford (1963) discussed the various units described here and gave thicknesses for Mount Wilson and other areas, as well as correlations of the various units. Short papers by Greggs (1963, p. 1-3) and Pelzer (1963, p. 4-13) sum- marize the present status of stratigraphic nomenclature and zonation of the Mons and Sarbach Formations in the Sunwapta Pass region and in the Southern Rocky Mountains in general.- The present paper is an outgrowth of a regional study of conodonts by D. L. Clark and R. L. Ethington, and Early Paleozoic sponges by J. K. Rigby. Locality and Method of Study A complete section of the Lyell( ?), Mons, Sarbach, Skoki, an unnamed Formation, and Mount Wilson Formations was measured during the summer cf 1963, along a small stream which drains past the campgrounds, east of the Chalet, at the Columbia Icefields, Jasper National Park, Alberta (Text-fig. 1). The section is well exposed and readily accessible. The section was measured with a tape. Thicknesses were calculated in the field using standard trigonometric techniques. Samples were collected for cono- donts, sponges, and lithology. ACKNOWLEDGMENTS Permission to collect in Banff and Jasper National Parks is gratefully acknowledged. Cooperation of officers of both Jasper and Banff National Parks is sincerely appreciated. Robert Pinney, Robert Hinds, and J. Keith Rigby, Jr. assisted in the field and in preparation of some of the samples. Some costs of sample and manuscript preparation, and travel were supported by National Science Foundation